#include <iostream>
#include <string>
using namespace std;

int main()
{
  string firstName = "John";
  string lastName = "Doe";
  string fullName = firstName + lastName;
  cout << fullName << endl;

  fullName = firstName + " " + lastName;
  cout << fullName << endl;

  fullName = firstName.append(lastName);
  cout << fullName << endl;

  string txt = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
  cout << "The length of the txt string is: " << txt.length() << endl;

  cout << "The length of the txt string is: " << txt.size() << endl;

  string myString = "Hello";
  cout << myString[0] << endl;

  myString[0] = 'J';
  cout << myString << endl;

  return 0;
}
